For all their technical advancements, smartphones still don't offer the sort of battery life we used to see in the handsets of yesteryear. One solution is to use a battery case, though these are often bulky and ugly. But if you're environmentally conscious, have a spare $4500, and are in the market for an iPhone X, Russian accessory maker Caviar has you covered.

First announced in November, the iPhone X Tesla consists of one of Apple's flagships with a phone case attached directly to the device and a solar panel on the back. This feeds into a dedicated battery that can juice the iPhone by pressing a button on the rear. Caviar hasn't revealed any technical details, unfortunately, but it claims to have carried out over 100 tests "proving the effectiveness and safety of this system."

The case is pretty thick, increasing the iPhone X's thickness up from 7.7mm to 16.2mm, but it does come with some luxury 24K gold trimmings, a battery charge indicator, and a gold plate showing its limited-edition credentials.

Caviar says it's making 999 units, the first of which is intended for Elon Musk and comes with the engraving "Made on Earth by Humans," a tribute to the Tesla launched into space by SpaceX.

$4600 gets you the 64GB iPhone X Tesla, but if you like your ostentatious handsets to come with more storage, there's also a $4800 256GB model.

Caviar has a history of selling expensive devices, including a $3000 Apple Watch that pays homage to Vladimir Putin, a $4300 iPhone 5S engraved with Putin's face, and a $2500 Nokia commemorating the Russian President's meeting with Donald Trump.